Sedimentological and Paleodepositional Studies of Outcropping Sediments in Parts of Southern Middle Niger Basin

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Author(s) Jerry Osokpor | Jahswill Okiti
Pages 839-846
Volume 2
Issue 12
Date December, 2013
Keywords Middle Niger Basin, Paleodepositional Environment, Lokoja Formation, Lithofacies, Mount Patti.

The determination of paleodepositional environment within which geologic factors interplayed to create various sedimentary facies and facies associations present in outcropping sediments in parts of the Southern Middle Niger Basin, in order to establish sedimentary architectures through detailed field mapping and laboratory techniques, forms the focus of this study. The Lokoja Formation was mapped on outcrops exposed in Robinson Street, Mount Patti, Banda and Filele in Lokoja area and along the Okene-Lokoja-Abuja express way. The study area lies within latitude N 070 81´ and N 080 30´; longitude E 0060 73´ and E 0060 86´ One main lithofacies, sand, and three sub-lithofacies (fine-grained sand, medium-grained sand, coarse-grained sand) were defined. Sorting ranged from 0.72 – 1.29, indicating poor – moderate sorting for the Lokoja Formation. Depositional environments defined by values of binary plots of skewness versus standard deviation mean versus standard deviation for samples obtained from the Lokoja area, confirmed by binary plot of skewness versus median for same samples indicate that sediments of the Lokoja Formation was deposited in a continental fluvial paleodepositional environment forming a progradational architecture that was generated during relative sea level fall in the adjoining Anambra Basin.

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